Plug-in type liquid atomizer

Abstract

A piezoelectrically actuated liquid atomizer device which applies alternating voltages from an ordinary wall outlet to a piezoelectric actuator intermittently and at a high rate sufficient to cause an atomization plate which is vibrated by the actuator to form small droplets from liquid which is supplied to the plate. The intermittent application of voltages to the piezoelectric actuator is carried out according to a duty cycle in which the off times are adjustable. An override of the duty cycle is provided so that the piezoelectric actuator operates continuously for intervals which are manually or automatically controlled.

1. A plug-in liquid atomizer comprising:
 a housing having a generally flat vertical surface;  
 a pair of prongs extending out from said vertical surface for plugging into a wall outlet;  
 a drive assembly mounted in said housing, said drive assembly comprising a piezoelectric actuator which expands and contracts in response to applied alternating electrical fields applied across opposite sides thereof and an atomizing plate coupled to and vibrated by the expansion and contraction of said actuator;  
 a first electrical interconnection between one of said prongs and one side of said piezoelectric actuator and a second electrical interconnection between the other of said prongs and an opposite side of said piezoelectric actuator, said first and second electrical interconnections being configured to apply alternating voltages from said prongs across said piezoelectric actuator at frequencies insufficient to produce atomization from said plate;  
 an electronic switch arranged in association with at least one of said first and second electrical interconnections to control the application of voltages from said prongs to said piezoelectric actuator; and  
 an oscillator connected to said electronic switch to open and close said switch at a rapid rate sufficient to cause said plate to atomize liquid applied thereto.  
 
   
   
     2. An atomizer according to  claim 1 , wherein a coil is interposed along one of said first and second electrical interconnections. 
   
   
     3. An atomizer according to  claim 1 , wherein a diode is interposed along one of said first and second electrical interconnections. 
   
   
     4. An atomizer according to  claim 1 , wherein a switch actuator control oscillator is connected to said electronic switch to control its operation. 
   
   
     5. An atomizer according to  claim 4 , wherein said switch actuator control oscillator is connected to be operated by electrical power from said prongs. 
   
   
     6. An atomizer according to  claim 4 , wherein said switch actuator control oscillator operates at a variable frequency. 
   
   
     7. An atomizer according to  claim 4 , wherein a duty cycle control circuit is connected to turn said switch actuator control oscillator off for predetermined lengths of time. 
   
   
     8. An atomizer according to  claim 7 , wherein said duty cycle control circuit is arranged to turn said switch actuator control oscillator on for a first predetermined length of time and off for an adjustable period of time. 
   
   
     9. An atomizer according to  claim 7 , wherein said duty cycle control circuit includes a duty cycle control oscillator. 
   
   
     10. An atomizer according to  claim 7 , wherein an override control circuit is connected to override said duty cycle control circuit and thereby maintain continuous operation of said switch actuator control oscillator for a given duration. 
   
   
     11. An atomizer according to  claim 10 , wherein said override control circuit is connected to prevent operation of said duty cycle control oscillator for said given duration. 
   
   
     12. An atomizer according to  claim 10 , wherein said override control circuit comprises a one shot circuit having a set duration corresponding to said given duration, said one shot circuit being connected to disable operation of said duty cycle control oscillator for said given duration. 
   
   
     13. An atomizer according to  claim 10 , wherein said override control circuit comprises a switch connected to prevent outputs from said duty cycle control oscillator from being applied to said switch actuator control oscillator. 
   
   
     14. A method of atomizing a liquid comprising the steps of:
 applying alternating voltages, which are received from an electrical outlet, through a pair of electrical interconnections to opposite sides of a piezoelectric actuator to cause said actuator to expand and contract and vibrate a plate which is coupled thereto, said plate being supplied with liquid to be atomized, said alternating voltages received from said electrical outlet having a frequency insufficient to produce atomization of liquid supplied to said plate; and  
 rapidly switching at least one of said electrical interconnections to rapidly connect and disconnect said piezoelectric actuator to and from said one interconnection whereby the alternating voltages which are supplied from said interconnections to said actuator, are applied across said actuator intermittently and at a sufficiently high rate to cause said actuator to vibrate said plate at a frequency which causes atomization of liquid supplied to the plate.  
 
   
   
     15. A method according to  claim 14 , wherein a coil is interposed along said one electrical interconnection and further including the step of connecting said one electrical interconnection to ground each time it is disconnected from said piezoelectric actuator. 
   
   
     16. A method according to  claim 14 , including the step of subjecting said alternating voltage to half wave rectification along one of said first and second electrical interconnections. 
   
   
     17. A method according to  claim 14 , including the step of rapidly switching is carried out by operating an electronic switch by means of an output from a switch actuator control oscillator. 
   
   
     18. A method according to  claim 17 , including the step of operating said switch actuator control oscillator with electrical power received from said electrical outlet. 
   
   
     19. A method according to  claim 17 , including the step of operating said switch actuator control oscillator at a variable frequency. 
   
   
     20. A method according to  claim 17 , including the step of turning said switch control oscillator off for predetermined lengths of time. 
   
   
     21. A method according to  claim 20 , including the step of turning said switch actuator control oscillator on for a first predetermined length of time and off for an adjustable period of time. 
   
   
     22. A method according to  claim 17 , wherein said actuator control oscillator is turned on and off by means of a duty cycle control oscillator. 
   
   
     23. A method according to  claim 22 , including the step of overriding said duty cycle control circuit to maintain continuous operation of said switch actuator control oscillator for a given duration. 
   
   
     24. A method according to  claim 22 , wherein said step of overriding is carried out in a manner to prevent operation of said duty cycle control oscillator for said given duration. 
   
   
     25. An atomizer according to  claim 22 , wherein said overriding is carried out by means of a one shot circuit having a set duration corresponding to said given duration, said one shot circuit being connected to disable operation of said duty cycle control oscillator for said given duration. 
   
   
     26. An atomizer according to  claim 22 , wherein said overriding is carried out by means of a switch which is connected to prevent outputs from said duty cycle control oscillator from being applied to said switch actuator control oscillator.